Joint direct injection and GC–MS chemometric approach for chemical profile and sulfur compounds of sesame-flavor Chinese Baijiu (Chinese liquor)

Abstract

Sesame-flavor Chinese Baijiu (SFCB) is a popular type of Chinese Baijiu because of its unique sesame-like aroma. Direct injection combined with gas chromatography–mass spectrometry (GC–MS) was successfully applied to determine volatile compounds in 36 sesame-flavor Chinese Baijiu (SFCB) samples and total of 125 volatile compounds were detected, 30 volatiles were further identified as impact aroma compounds of Guojing SFCB by aroma extract dilution analysis (AEDA). As a category of characteristic aroma compounds of SFCB, five sulfur compounds detected were quantified by internal standard method followed by GC–MS with Selected Ion Monitor (GC–MS/SIM). The contents of dimethyl disulfide and dimethyl trisulfide in most SFCB samples were extremely higher than their olfactory thresholds, which indicated these sulfur compounds made significant contribution to the aroma profile of SFCB. Composition differences between the SFCB samples of various brands were investigated. Statistical analyses on the contents of sulfur compounds and peak area data were used to distinguish SFCB samples from different brands. The results of correlation cluster analysis and principal component analysis (PCA) showed that a group of common volatile compounds appeared to occur in the SFCB samples of different brands and may constitute the aromatic skeleton for SFCB although a few particular volatiles were found to be specific for the samples of a certain brand. Therefore, differences between SFCB samples were more likely due to the distinguishing balance states established by the group of common volatiles with different concentrations rather than the presence of specific volatiles with unique aromas.